ReanGD/go-web-search

package werrors

import (
    "fmt"
    "path/filepath"
    "runtime"

    "github.com/uber-go/zap"
)

// LogLevel level for logging
type LogLevel int32

// ErrFailedGetCaller - error get caller
const ErrFailedGetCaller = "Failed to get caller"

// ErrorEx - error with extended fields
type ErrorEx struct {
    msg    string
    Level  zap.Level
    Fields []zap.Field
}

func (e ErrorEx) Error() string {
    return e.msg
}

var callerSkip = 3
var callerTest = false

func getCaller() string {
    if callerTest {
        return "<fake>"
    }
    ps, file, line, ok := runtime.Caller(callerSkip)
    if !ok {
        return ErrFailedGetCaller
    }

    return fmt.Sprintf("[%s:%d] %s", filepath.Base(file), line, filepath.Base(runtime.FuncForPC(ps).Name()))
}

func newError(logLevel zap.Level, msg string, fields ...zap.Field) error {
    result := &ErrorEx{
        msg:    msg,
        Level:  logLevel,
        Fields: make([]zap.Field, len(fields)+1)}

    result.Fields[0] = zap.String("caller", getCaller())
    for i, field := range fields {
        result.Fields[i+1] = field
    }

    return result
}

// NewEx - create error with all fields
func NewEx(logLevel zap.Level, msg string, fields ...zap.Field) error {
    return newError(logLevel, msg, fields...)
}

// New - create error with caller only
func New(msg string) error {
    return newError(zap.ErrorLevel, msg)
}

// NewLevel - create error with caller and log level
func NewLevel(logLevel zap.Level, msg string) error {
    return newError(logLevel, msg)
}

// NewDetails - create error with caller and details message
func NewDetails(msg string, details error) error {
    return newError(zap.ErrorLevel, msg, zap.String("details", details.Error()))
}

// NewFields - create error with custom fields
func NewFields(msg string, fields ...zap.Field) error {
    return newError(zap.ErrorLevel, msg, fields...)
}

// AddFields - add new fields for error
func AddFields(err error, fields ...zap.Field) error {
    werr, ok := err.(*ErrorEx)
    if !ok {
        return newError(zap.ErrorLevel, err.Error(), fields...)
    }
    for _, field := range fields {
        werr.Fields = append(werr.Fields, field)
    }
    return werr
}

// LogError - write error to zap log
func LogError(logger zap.Logger, err error) {
    werr, ok := err.(*ErrorEx)
    if !ok {
        logger.Error(err.Error())
    } else {
        logger.Log(werr.Level, werr.Error(), werr.Fields...)
    }
}